IamCheEng Magazine 6-2013

We reached

Likes in 10,000+

M A G A Z I N E

https://www.facebook.com/IamCheEng

6/2013

For your support

I am a Chemical Engineer We discuss Chemical Engineering and

provide some information and news. We would like to think of our page as an

exchange page of experience and information.


Slogan Connecting chemical engineers.

Vision Improving the chemical Engineering skills to meet the work environment & to decrease the gap between study and work.

Mission Gathering information about any chemical engineering fields.

What Is Chemical Engineering? Chemical engineering basically is applied chemistry. It is the branch of engineering concerned with the design, construction, and operation of machines and plants that perform chemical reactions to solve practical problems or make useful products.

What Is a Chemical Engineer? Like all engineers, chemical engineers use math, physics, and economics to solve technical problems. The difference between chemical engineers and other types of engineers is that they apply a knowledge of chemistry in addition to other engineering disciplines. Chemical engineers sometimes are called 'universal engineers' because their scientific and technical mastery is so broad.

What Do Chemical Engineers Do? Some chemical engineers make designs and invent new processes. Some construct instruments and facilities. Some plan and operate facilities. Chemical engineers have helped develop atomic science, polymers, paper, dyes, drugs, plastics, fertilizers, foods, petrochemicals... pretty much everything. They devise ways to make products from raw materials and ways to convert one material into another useful form. Chemical engineers can make processes more cost effective or more environmentally friendly or more efficient. As you can see, a chemical engineer can find a niche in any scientific or engineering field.

Learn something about everything

What is the Function of a Gate Valve? Definition A gate valve, also referred to as a sluice valve, is a valve that opens and closes to regulate fluid flow. A gate valve opens by lifting a rectangular or round gate or wedge, often called a sliding door, out of the fluid's path to allow it to flow though. Function Gate valves are used in straight-flow fluid systems where a minimum amount of friction is required. Unlike other valves, gate valves are constructed to be used either completely open or closed. If partially open, the fluid velocity can damage the gate valve's seal and cause leakage. Stems Gate valves contain either a non-rising or rising stem. Rising stems are used as a visual indication of the valve position and lift when a valve is open. Non-rising stems are used for underground gate valves or when vertical space is constricted.

Different types of Flowmeters with their Diagrams : i. Orifice Flowmeter ii. Venturi Flowmeter iii. Nozzle Flowmeter iv . Pitot Tube Flowmeter v. Wedge Flowmeter vi. Vortex Flowmeter vii. Ultrasonic Flowmeter viii. Turbine Flowmeter ix. Magnetic Flowmeter

Manometer A Manometer is a device which can be used to measure pressure of fluids(i.e liquids and Gases). PRINCIPLE: Manometers are those pressure measuring devices which are based on the principle of balancing the column of liquid (whose pressure is to be found) by the same or another column of liquid. They are of two types 1. simple manometers 2. Differential manometers simple manometers are those which measure pressure at a point in a fluid containing in the pipe or a vessel. On the other hand Differential manometers measure the difference of pressure between any two points in a fluid contained in a pipe or vessel.

Feedforward Control : In contrast to feedback control, feedforward control acts the moment a disturbance occurs, without having to wait for a deviation in process variable. This enables a feedforward controller to quickly and directly cancel out the effect of a disturbance. To do this, a feedforward controller produces its control action based on a measurement of the disturbance. When used, feedforward control is almost always implemented as an add-on to feedback control. The feedforward controller takes care of the major disturbance, and the feedback controller takes care of everything else that might cause the process variable to deviate from its set point.

In our example of the heat exchanger, in which the major disturbances come from changes in process flow rate, the latter can be measured and used for adjusting the steam flow rate proportionally. This is done by the feedforward controller.

Implementing Feedforward Control : Many PID controllers have an external connection for adding an input from a feedforward controller. Otherwise the output of the feedforward controller can be externally added to the output of the feedback controller. Review your controller documentation and take special care with scaling the feedforward signal. Many PID controllers expect the feedforward signal to be scaled between -100% and +100%.

Feedforward and feedback control is often combined with cascade control, to ensure that their control actions manipulate the physical process linearly, eliminating control valve nonlinearities and mechanical problems. If several major disturbances exist, a feedforward controller can be implemented for each of them. The outputs of all the feedforward controllers can be added together to produce one final feedforward signal. Only consider disturbances that meet these criteria: Measurable if it cant be measured you cant control from it Predictable effect on the process variable most disturbances will fall in this class Occur so rapidly that the feedback control cannot deal with them as they happen.

Cascade Control : Cascade Control Systems contain integrated sets of control loops * Primary Loop: Monitors the control variable and uses deviation from its setpoint to provide an output to the secondary loop. * Secondary Loop: Receives its setpoint from the primary loop and controls the reference variable accordingly.

Benefits of Cascade Control 1- Effectively accounts for external disturbances 2- Reduces dead time in variable response 3- Compatible with other Control Systems, such as Feed-Back and Feed-Forward Control Architectures

Disadvantages of Cascade Control 1- Multiple control loops make physical and computational architecture more complex 2- Additional controllers and sensors can be costly

What is the Difference between rising stem gate valve and non rising stem gate valve? Rising stem gate Valve - Stem threads are out side of valve body and in no contact with fluid medium. Stem rises while opening the valve (by hand wheel). Since the stem threads are located outside obviously it needs some more vertical clearance space while opening the valve. Non Rising Stem gate Valve - Stem threads are inside the the valve body and it is in contact with fluid medium. Hence, lot of chances for fouling the threads and these types of valves only can be used in clean liquids and gases. Less vertical clearance space required while opening the valve.

Foot valve: a check valve on the foot of a suction line to prevent back-flow. A suction valve or check valve at the lower end of a pipe; esp., such a valve in a steam-engine condenser opening to the air pump. -A foot valve is nothing more than a swing check valve operating in the vertical position at the the liquid entry to the vertical suction line of a sump pump or another type of pump that has a negative suction lift due to gravity - i.e., the pump is usually located above the liquid level of the suction vessel or container. If there is any logic in this description it is that the check valve is located at the "foot" of the vertical pipe run. But it has to be understood that we are talking about a check valve - not another type of valve. The function of a foot valve is to contain the liquid inventory within the pump casing and the suction line in the event the pump is shut down or stopped. This action preserves the liquid priming of the pump and allows for a successful, instant liquid pumping start up during the next, subsequent pump start-up. This is especially useful when the pump is started from an isolated location and there is no one around to manually prime the pump with liquid prior to start up.

Float type steam trap : The Float type steam trap consists of a chamber having inlet and outlet ports. The chamber contains a stainless steel ball-float connected by a lever to the inside of the chamber wall. In the body of the trap, the outlet port has valve seats fitted to accommodate a valve plug which is fitted to the lever between the float and the chamber wall. When the trap is empty, the ball float is down and the outlet valve is closed. As condensate (water) enters the trap and forms a level, the ball begins to float and rise with the rising level. At a pre-set level the rising lever actuates the valve plug and opens the valve. Condensate passes out of the trap, the level falls and the valve closes down. In this way, the level of condensate is controlled and no steam loss is incurred. This type of trap works well with heavy or light condensate loads.

THE THERMOSTATIC STEAM TRAP This type of steam trap has a sealed, internal bellows element filled with a liquid which has a boiling point about 25C below that of water. Heating or cooling of the element causes it to expand or contract. The bottom of the element is connected to a valve which fits into a seat in the trap body. When the trap contains steam, the bellows is expanded by boiling the liquid inside and the valve is closed. As condensate fills the trap, it cools and the bellows begins to contract as its internal liquid stops boiling. This opens the valve and the liquid is drained off and then replaced by steam. Once again the bellows expands and closes the valve.

Relief Valves : * Pressure relief valve - A spring-loaded pressure relief valve which is designed to open to relieve excess pressure and to reclose and prevent the further flow of fluid after normal conditions have been restored. It is characterised by a rapid-opening 'pop' action or by opening in a manner generally proportional to the increase in pressure over the opening pressure. It may be used for either compressible or incompressible fluids, depending on design, adjustment, or application. This is a general term, which includes safety valves, relief valves and safety relief valves. Safety valve - A pressure relief valve actuated by inlet static pressure and characterized by rapid opening or pop action. Safety valves are primarily used with compressible gases and in particular for steam and air services. However, they can also be used for process type applications where they may be needed to protect the plant or to prevent spoilage of the product being processed.

Relief Valves : * Relief valve - A pressure relief device actuated by inlet static pressure having a gradual lift generally proportional to the increase in pressure over opening pressure. Relief valves are commonly used in liquid systems, especially for lower capacities and thermal expansion duty. They can also be used on pumped systems as pressure overspill devices. * Safety relief valve - A pressure relief valve characterised by rapid opening or pop action, or by opening in proportion to the increase in pressure over the opening pressure, depending on the application, and which may be used either for liquid or compressible fluid. In general, the safety relief valve will perform as a safety valve when used in a compressible gas system, but it will open in proportion to the overpressure when used in liquid systems, as would a relief valve.

Fluidized-Bed Heat Exchangers: In a uidized-bed heat exchanger, one side of a two-uid exchanger is immersed in a bed of nely divided solid material, such as a tube bundle immersed in a bed of sand or coal particles. At a proper value of the uid velocity, the upward drag force is slightly higher than the weight of the bed particles. As a result, the solid particles will oat with an increase in bed volume, and the bed behaves as a liquid. This results in a uniform temperature for the total bed with an apparent thermal conductivity of the solid particles as innity. Chemical reaction is common on the uidized side in many process applications, and combustion takes place in coal combustion uidized beds. The common applications of the uidized-bed heat exchanger are drying, mixing, adsorption, reactor engineering, coal combustion, and waste heat recovery.

There are four processes in the Rankine cycle. These states are identified by numbers (in brown) in the above Ts diagram. Process 1-2: The working fluid is pumped from low to high pressure. As the fluid is a liquid at this stage the pump requires little input energy. Process 2-3: The high pressure liquid enters a boiler where it is heated at constant pressure by an external heat source to become a dry saturated vapor. The input energy required can be easily calculated using mollier diagram or h-s chart or enthalpy-entropy chart also known as steam tables.

Process 3-4: The dry saturated vapor expands through a turbine, generating power. This decreases the temperature and pressure of the vapor, and some condensation may occur. The output in this process can be easily calculated using the Enthalpy-entropy chart or the steam tables. Process 4-1: The wet vapor then enters a condenser where it is condensed at a constant temperature to become a saturated liquid. by the condensers.

In an ideal Rankine cycle the pump and turbine would be isentropic, i.e., the pump and turbine would generate no entropy and hence maximize the net work output. Processes 1-2 and 3-4 would be represented by vertical lines on the T-S diagram and more closely resemble that of the Carnot cycle. The Rankine cycle shown here prevents the vapor ending up in the superheat region after the expansion in the turbine,which reduces the energy removed by the condensers.

THERMO-DYNAMIC STEAM TRAP: This type of steam trap, when installed, has a strainer fitted into the line upstream of it, to remove solid particles of scale . .etc. As condensate enters the trap, through the inlet pipe with the steam pressure behind it, a metal disc is forced upwards into a small chamber and the condensate passes under the disc into the outlet pipe. The velocity of the water passing through the trap is low, even when the pressure is high. This is due to the density of the water being high compared to that of steam and the fact that, within the trap, the fluids pass through an angle of 180. When all of the water has been displaced, steam begins to flow. The greater velocity of the steam below the disc and the sudden change of direction, causes a pressure drop under the disc which pulls it down onto its seat and stops the steam flow. The steam pressure in the chamber above the disc will be the same as the line pressure thereby holding the disc on its seat. When the steam above the disc cools and condenses, the chamber pressure falls and the disc is forced upwards again by the line pressure. If only steam passes into the trap, the above process is repeated with a small release of steam until the disc drops again.

AN INTRODUCTION TO PUMPING EQUIPMENT

Every magazine we will introduce a special course, Today our course is PUMP

AN INTRODUCTION TO PUMPING EQUIPMENT WHAT IS THE PUMP? Pumps are machines which supply energy to a liquid in order to move it from place to another. The method that is used to supply this energy to the liquid determines the category into which the pump is placed and the system between the pump and the liquid final destination defines the application.

Pumps enable a liquid to: 1. Flow from a region or low pressure to one of high pressure. 2. Flow from a low level to a higher level. 3. Flow at a faster rate.

Refinery Water Flood

Transportation

AN INTRODUCTION TO PUMPING EQUIPMENT Pumps vary considerably in their size, construction and principle of operation.

There are two main categories of pump: Rotodynamic pumps. Positive displacement pumps.

Diaphragm

Piston

Plunger

Reciprocating Rotary

Mixed flow Gear

Lobe

Sliding Vane

Screw

Axial flow

Centrifugal

Rotodynamic

Turbine

PUMP

Positive displacement


Centrifugal Pumps: Also known as rotary pumps, centrifugal pumps have a rotating impeller, also known as a blade, that is immersed in the liquid. Liquid enters the pump near the axis of the impeller, and the rotating impeller sweeps the liquid out toward the ends of the impeller blades at high pressure. For low flows and high pressures, the action of the impeller is largely radial. For higher flows and lower discharge pressures, the direction of the flow within the pump is more nearly parallel to the axis of the shaft, and the pump is said to have an axial flow. The impeller in this case acts as a propeller. The transition from one set of flow conditions to the other is gradual, and for intermediate conditions, the device is called a mixed-flow pump.


Positive-displacement Pumps: A variety of positive-displacement pumps are also available, generally consisting of a rotating member with a number of lobes that move in a close-fitting casing. The liquid is trapped in the spaces between the lobes and then discharged into a region of higher pressure. A common device of this type is the gear pump, which consists of a pair of meshing gears. The lobes in this case are the gear teeth.

What is the main difference between kinetic and positive displacement pumps ? The main difference between kinetic and positive displacement pumps lies in the method of fluid transfer. A kinetic pump imparts velocity energy to the fluid, which is converted to pressure energy upon exiting the pump casing

AN INTRODUCTION TO PUMPING EQUIPMENT A positive displacement pump moves a fixed volume of fluid within the pump casing by applying a force to moveable boundaries containing the fluid volume. Positive displacement pumps are also divided into two major pump categories : reciprocating & rotary. Reciprocating pumps transfer a volume of fluid by a crankshaft,eccentric cam or an alternating fluid pressure acting on a piston, plunger or a diaphragm in a reciprocating motion. The Table below outlines some of the main differences between centrifugal pumps, reciprocating pumps and rotary pumps. Note that centrifugal, reciprocating and rotary pumps are all relatively broad categories. The table below provides a comparison of features between these pump categories that generally holds true. Also, note that Table lists typical maximum flow rates and heads. It is possible to build special pumps outside the upper bounds of the pressures and flow rates listed, but such pumps would be prohibitively expensive for most applications.


Rotary Pumps Reciprocating

Pumps Centrifugal Pumps Parameter

Low/Medium

Capacity,

Low/Medium

Pressure

Low Capacity,

High Pressure

Medium/High Capacity,

Low/Medium Pressure

Optimum Flow and

Pressure

Applications

10,000+ GPM 10,000+ GPM 100,000+ GPM Maximum Flow

Rate

Yes Yes No Low Flow Rate

Capability

4,000+ PSI 100,000+ PSI 6,000+ PSI Maximum Pressure

Yes Yes No Requires Relief

Valve

Smooth Pulsating Smooth Smooth or

Pulsating Flow

Constant Constant Variable Variable or

Constant Flow

Yes Yes No Self-priming

Requires Less Space Requires More

Space

Requires Less Space Space

Considerations

Lower Initial

Lower Maintenance

Lower Power

Higher Initial

Higher Maintenance

Lower Power

Lower Initial

Lower Maintenance

Higher Power

Costs

Requires clean,

clear, non-abrasive

fluid due to close

tolerances

Optimum

performance with

high viscosity fluids

Higher tolerance for

entrained gases

Suitable for clean,

clear, non-abrasive

fluids. Specially-

fitted pumps suitable

for abrasive-slurry

service.

Suitable for high

viscosity fluids

Higher tolerance for

entrained gases

Suitable for a wide

range including clean,

clear, non-abrasive

fluids to fluids with

abrasive, high-solid

content.

Not suitable for high

viscosity fluids

Lower tolerance for

entrained gases

Fluid Handling


Centrifugal Pumps Capacity: The wide variety of centrifugal pumps manufactured offer a relatively large range of available capacities. Radial-flow and mixed flow pumps are used for low to medium capacity applications. For high capacity applications, axial-flow pumps are capable of delivering flow rates in excess of 100,000 gpm. Centrifugal pumps are not stable at low flow rates, although there are special low-flow centrifugal pumps available that can deliver flow rates less than 10 gpm. However, for extreme low-flow applications (< 1 gpm), positive displacement pumps are a better selection.

Reciprocating & Rotary Pumps Capacity: Reciprocating and rotary pumps are capable of capacities ranging from low to medium, with flow rates peaking at 10,000+ gpm. In theory, reciprocating pumps can be manufactured to deliver more capacity, but they become prohibitively large and expensive at high flow rates. Both reciprocating and rotary pumps are capable of delivering product at extremely low flow rates (fractions of a gpm), making them particularly suitable for many chemical injection applications.


Why it is necessary to install a relief valve on the discharge of the Reciprocating or Rotary pumps ? Because both reciprocating and rotary pumps will continually increase pressure when pumping against a closed discharge to the extent allowed by the drivers horsepower. This can result in overpressure of the pump or piping components, so it is necessary to install a relief valve on the discharge of the pump capable of discharging the full capacity of the pump.

Why it is not necessary to install a relief valve on the discharge of the Centrifugal pumps ? A centrifugal pumps pressure rise is limited to the shut-off pressure on the pump curve, which is always less than the design pressure of the pump (and the piping system if properly designed). A relief valve is only needed if no other measures are provided to detect low flow conditions and shut down the pump to prevent damage. The relief valve need only be sized to pass the minimum flow rate required to maintain stable flow and prevent excessive temperature rise.


Centrifugal pumps and most rotary pumps provide smooth, non-pulsating flow, while reciprocating pumps produce a pulsating flow. A pulsating flow may require special design considerations in the piping system. If the pump is not located near the suction source, then acceleration head can contribute to low NPSHA problems, which may require the installation of a suction stabilizer. A pulsation dampener may need to be installed in the discharge piping to reduce pressure surges resulting from the pulsating flow.

Centrifugal Pumps Variable or Constant Flow: Centrifugal pumps operate on a variable-flow, variable-head curve. As the discharge pressure decreases, the pump delivers a higher flow rate. Centrifugal pumps are favored where process conditions often require varying flow rates. For example, a level control valve must throttle the flow rate from a vessel to maintain a constant level in the vessel. A centrifugal pump is well suited to handle this process condition.


Reciprocating & Rotary Pumps Variable or Constant Flow: At any given speed, reciprocating and rotary pumps operate at a constant flow rate regardless of the discharge pressure. There are specific applications that require either constant flow or variable flow. Metering pumps rely on a constant flow at varying pressures, which makes reciprocating pumps and rotary pumps suitable for this application. Piston pumps used for metering will often use an adjustable stroke length to allow the operator to vary the flow rate to meet the system requirements. whereas a positive displacement pump would either require a continuous recycle to suction or a variable speed driver to accommodate the variable flow.

Self-priming : Reciprocating and rotary pumps are self-priming. This is an important consideration where a prime cannot be maintained on the pump. Centrifugal pumps are not inherently self-priming, although some manufacturers do specially design self-priming units. External priming sources, such as an eductor or vacuum pump can also be employed.


Costs Considerations : The reciprocating pump will generally have higher initial capital costs and will require more space relative to the centrifugal pump or the rotary pump. The reciprocating pump will generally have higher maintenance costs relative to the centrifugal pump or the rotary pump. The centrifugal pump will generally have higher annual power consumption costs relative to the reciprocating pump or the rotary pump because of lower efficiencies.

Costs Considerations : A pump that is selected for an application outside of its optimum operating parameters will almost certainly not follow these rules. For example, a rotary pump operating in a high pressure, abrasive-slurry service would probably have higher maintenance costs than a properly selected reciprocating pump. The close running clearances (particularly for high pressure service) required in the rotary pump would likely result in premature wear and frequent maintenance.


Centrifugal Pumps Fluid Handling: Centrifugal pumps are suitable for transferring a variety of fluids ranging from clean, clear non-abrasive fluids to abrasive-slurries. However, a centrifugal pump is not the best choice for pumping highly viscous fluids due to dramatic drops in efficiency at high viscosities. Centrifugal pumps are not normally specified for viscosities higher than about 4,000 SSU. Centrifugal pumps are also not well suited to pumping entrained air. Most centrifugal pumps can handle up to about 2% entrained gas and specially-designed pumps can handle up to about 10%.

Reciprocating Pumps Fluid Handling: Reciprocating pumps are well suited for transferring clear, non-abrasive fluids, as well as abrasive slurries. In fact, the relatively low velocities of moving parts within a reciprocating pump make it particularly resistant to erosion in abrasive-slurry applications, provided that the pump is properly designed for the service. Reciprocating pumps maintain high efficiencies when pumping highly viscous fluids and can easily handle 50% and higher volumes of entrained gas.


Rotary Pumps Fluid Handling: Rotary pumps can also handle high viscosity fluids and high volumes of entrained gas. In fact, many rotary pumps operate at their best efficiency at higher viscosities. However, rotary pumps are not well suited for pumping corrosive fluids or fluids with abrasive solids because of close clearances between rotating and static pump components.

Summary One fact that must always be remembered: A pump does not create pressure, it only provides flow. Pressure is a just an indication of the amount of resistance to flow. there are many different subcategories of pumps within these broad categories and there are many regions of overlap where multiple types of pumps in the same category and even in different categories would be suitable. Since every pump application is unique, each of the factors that influence the pump selection must be considered in detail.

Learn how to have a successful job

interview

The fluid property, due to which, mercury does not wet the

glass is

A. surface tension

B. viscosity

C. cohesion

D. Adhesion

Laminar flow of a Newtonion fluid ceases to exist, when the

Reynolds number exceeds

A. 4000

B. 1500

C. 2100

D. 3000

The normal stress is the same in all directions at a point in

a fluid, when the fluid is

A. non-viscous.

B. incompressible.

C. both (a) and (b).

D. having no motion of one fluid layer relative to the other.

Head developed by a centrifugal pump depends on its

A. speed

B. impeller diameter

C. both (a) and (b)

D. neither (a) nor (b)

Learn how to have

a successful job interview

In Centrifugal compressors, why does surge occurs?

A. Surge occurs due to low pressure in the suction drum.

B. Surge occurs due to low flow at suction.

C. Surge occurs due to high speed.

D. None of the above (neither A, nor B, nor C)

Loading/unloading ethylene requires:

A. Loading arm overhaul

B. Loading arm dismantling

C. Loading arm cooling-down


Why is pH measured in the boiler blowdown?

A. To adjust the flow

B. To prevent corrosion

C. To inject detergent

D. To inject polyelectrolyte

What is the physical meaning of saturated steam?

A. It is a steam at low pressure.

B. Steam at Dew point or at a point where all water

transferred to vapor.

C. It is a steam at high pressure.


Sulphur dust is:

A. Irritant & flammable

B. Irritant and toxic

C. Toxic

D. Corrosive only

Learn how to have


Which of the following statement is not correct?

A. Traceability of the product is optional

B. Processes transform inputs into outputs

C. Quality policy determines organisational objectives

D. Efficiency is the relationship between result and resources

In steam boilers, why is a continuous blowdown provided.

A. To control level in steam boiler.

B. To control the quality of steam.

C. To control the pressure.

D. All the above (A + B + C).

What is the purpose of the fast purging in a steam boiler?

A. To remove the sludge from the boiler bottom

B. To replace part of the water with fresh make-up water

C. To sample the water to check for composition

D. To check the level inside the boiler drum

Which of the following is not a quality principle?

A. Customer focus

B. Continuous improvement

C. Process approach

D. Maximum production on-specification

How many carbon moles are in 6.00 g of C?

A. Two moles.

B. Three moles.

C. Half mole.

D. One mole.

Learn how to have


On process plants why are process/utilities connections

equipped with flexibles and specific fittings?

A. To make sure operator will recognize them

B. To prevent any mix of utilities

C. To facilitate the work of the operator

D. To prevent purging with the wrong utility and/or

hydrocarbon contamination

In a distillation column, what is flooding?

A. It is the level increase in the column.

B. Pressure drop in the column.

C. It occurs when the liquid/vapour traffic is disturbed due

to high velocity of the vapour and liquid is entrained

upwards.

D. It occurs when the liquid/vapour traffic is disturbed due to

low velocity of the vapour and liquid weeps through the plates.

In a distillation column, what is the sensitive tray?

A. It is the tray at which the feed to the column is placed in

order to minimize temperature upsets.

B. It is the tray at which temperature in the stripping

section is controlled.

C. It is the tray at which most of the light and heavy

components are separated and fractionation occurs.


Learn how to have


For centrifugal pumps, what is cavitation?

A. Cavitation occurs due to low level in suction drum.

B. Cavitation occurs when the NPSH available is less than

the required NPSH.

C. It is the presence of vapour in the suction drum.

D. None of the above(neither A, nor B, nor C)

Why is saturated steam used in the different reboilers in the

plant and not superheated steam?

A. To prevent corrosion

B. To reduce reboiler duty

C. To limit thermal exchange

D. None of the above(neither A, nor B, nor C)

For steam turbines, why is heating necessary before start

up?

A. To get more power.

B. More discharge pressure.

C. More speed.

D. To avoid thermal shock.

What is Latent Heat?

A. It is the heat of a substance at ambient temperature.

B. Heat required to vaporise or to condense a gas.

C. Heat required to increase the temperature of 1 kg a

substance by 1C.

D. Heat required to melt or to freeze a liquid.

Learn how to have


What is Partial Pressure?

A. It is the pressure of a substance at ambient temperature.

B. Pressure required to vaporize or to condense a gas.

C. It is the pressure of individual component in a mixture

of gas.


What is Boiling Point?

A. It is the temperature required to vaporize the liquid.

B. Pressure and temperature drop in the column.

C. It is the temperature at which the vapour pressure of a

liquid is equal to the atmospheric pressure.


The net positive suction head (NPSH) of a centrifugal pump

is defined as the sum of the velocity head and the pressure

head at the

A. discharge.

B. suction.

C. suction minus vapor pressure of the liquid at suction

temperature.

D. discharge minus vapor pressure of the liquid at the

discharge temperature.

Pour point and freezing point is equal for

A. petrol

B. diesel

C. water

D. crude petroleum

Learn how to have


In cracking furnaces or fired heaters, what is the advantage

of using excess air in combustion?

A. Fuel consumption will be reduced.

B. Temperature will be better.

C. Complete combustion is ensured.


Which of the following fractions of a crude oil will have the

maximum gravity API (i.e. API) ?

A. Diesel

B. Gasoline

C. Atmospheric gas oil

D. Vacuum gas oil

Short distance transportation of grain, gravel, sand, ash,

asphalt etc. is done by using a __________ conveyor.

A. flight

B. slat or drag

C. ribbon

D. screw

Friction factor for fluid flow in pipe does not depend upon

the

A. pipe length.

B. pipe roughness.

C. fluid density & viscosity.

D. mass flow rate of fluid.

Learn how to have


Which one of the following is incombustible ?

A. H2 B. C2H2

C. CCl4 D. S

Fog is an example of colloidal system of

A. solid dispersed in gas.

B. solid dispersed in liquid.

C. liquid dispersed in gas.

D. gas dispersed in liquid.

In troposphere (the weather domain), the temperature 't' at

height 'h' above the sea level in metres is given by (where,

temperature at sea level is 15C and t is in C.)

A. t = 15 - 0.0065 h

B. t = 15 + 0.0065 h

C. t = 0.0035 h - 15

D. t = 15 - 0.0035 h

A high pressure boiler generates steam at a pressure greater

than __________ kg/cm2 .

A. 10 B. 50

C. 30 D. 80

Which of the following is not categorised as a "mechanical

operation" ?

A. Agitation

B. Filtration

C. Size enlargement

D. Humidification

Learn how to have


What is the kind of the following valve ?

slide valve gate valve

wafer check valve

expansion valve

Learn how to have


What is the kind of the following valve ?

needle valve

Foot valve

Butterfly Valve

non return valve or one way valve or check valve

Learn how to have


Send your question and we will post it on our page wall

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l

ONE of page fans has a question and needs an answer

LIST of QUESTIONS

1. i wanna attempt to construct a viable home based ammonia or urea production unit. using methane or LPG. In your opinion, is this possible to do profitably? And if it is cud u send me links to some literature that may help me out. Thanks in advance

2. If there any chemical which when mixed with water gives specific density higher than if water was mixed with Baryte?

3. What is yield of a process ? 4. What are differences between HETP and HTU for

column 5. could you give me some information for the glycerin

process 6. Difference between total dead heat & dead head at

max. impeller centrifugal pump 7. Is stichoimetry compulsory for chemical engineering ? 8. dose the activation energy change with particle size

when finding the rate equation? or in another way dose the activation energy affect with the particle size when finding the rate equation?

9. What chemical reaction not exothermic or endothermic or third way is possible or not ?

10. I want references about bio gas plz 11. how to prepare organic fertilizer at home from domestic

waste?

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


LIST of QUESTIONS

12. if non condensable is added inthe distillation column , so what's the effect in the dew point of the distillate . .whether it will increase or decrease? And why

13. What is the cheapest form of polymer? 14. What is the difference between a simple and long chain

polymer? 15. can any one help me to find information about Harriot

method for calculation of diffusion coefficient 16. what is the MAX temperature allowable for a heat

exchanger AS CWS COOLING WATER SUPPLY ? 17. can you give me references for production of dimethyl

ether 18. What role does the Ventury effect have on mixing

chemicals? 19. How can i check the purity of Kcl? 20. Which chemical will you add to water to increase the

viscocity to 40 centipose? 21. Esterification reaction is endothermic or exothermic? 22. can u suggest me whether chemical engg. Hv scope in

India...? 23. What is the difference between extensive and intensive

properties ? 24. can u explaine about split type heat exchanger 25. How much water occupy in a 1" inch s.s pipe of length

10 meter ??? How can we calculate?

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


LIST of QUESTIONS

26. What is wet vacuum and dry vacuum and compare both 27. why hydrogen is exception for joule thomson effect? 28. i want to know where the distillation coulumn will be

used in a horizontal position? and how will be the operating conditiones?

29. Can we use CSTR for gaseous reactant ? 30. Can we use liquid DAP instead of granules? As it will

reduce the cost of granulation,drying, cooling 31. Would you please tell me what is the maximum suction

head for centrifugal pump in case of negative suction?? 32. xplain d principles of the heat xchanger wen fluid flows

counter currently 33. how nuclear fusion and fission will takes place at a time

in hydrogen bomb? 34. uses of vinyl sulphone ester ?

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Tawedzerwa Masuka

i wanna attempt to construct a viable home based ammonia or urea production unit. using methane or LPG. In your opinion, is this possible to do profitably? And if it is cud u send me links to some literature that may help me out. Thanks in advance

Name comment

Ah.yehia this attach will help you http://www.mediafire.com/download/w7ftn158rtbinx3/ammonia.rar

Nidhi Satwara

If there any chemical which when mixed with water gives specific density higher than if water was mixed with Baryte?

Name comment

Er Dhaval Patel Molybdenum sulphate with solution pH 4-5.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Atul Gourh

What is yield of a process ?

Name comment

Ah.yehia

The yield of a chip manufacturing process refers to how much salable product is able to be produced. This can be an absolute number (chips per day for example) or a factor that refers to the percentage of total chips manufactured that passed inspection and were able to be sold. Of course, the higher the yield, the more chips that can be produced for (basically) the same cost, which allows costs and hence prices to decrease. http://www.pcguide.com/ref/cpu/char/mfgYield-c.html http://www.sixsigmatraining.org/six-sigma-projects/how-to-calculate-process-yields.html

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Atul Gourh


Name comment

Ah.yehia A manufacturing process has a 70% yield, meaning that 70% of the products are acceptable and 30% are defective

Abdelrahman Mohamed

Khalid

i think yield means that the product we need & and remaining byproducts aren't important like the main one.

Mohamed Wageeh

amount of desired product/amount of undesired product(from side reaction)

Hussam Nabawy or even from a single step reaction.. but in this case a yield of a reaction will express the conversion!!

Naveed Ali Koondhar

Simply we can say the rate of production

Saad Raad the desired material(product)/total material(feed)

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Atul Gourh


Name comment

Yuosuf Al Faraj

the yield is simply what we have got as a product at the end of the process. yield is related to the product while conversion related to the reactant .

Syed Shah Jehan Gillani

MEASURE OF PRODUCTIVITY HOW EFFICIENTLY GETTING THE THEORETICAL MAX.POSSIBLE OUTPUT BY GIVING SPECIFIC INPUT

Mohamed Hassn

Waheed

I think it is the percentage of conversion from input raw material to the main product

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Tarkeshwar Pandey

What are differences between HETP and HTU for column

Name comment

Nickkhil Batra hetp =height eqivalent to theoretical stage .it is height of packing that provides seperation equal to tray

Nickkhil Batra whereas htu is height of transfer unit which shows seperation efiiceincy of packinh

Prince Singla

Nickkhil: if HETU=HTU then wat u interpret about operating line and equilibrium line.....means are they coincide or // or perpendicular...??

Nickkhil Batra i think operating lines are parallel in that case

Z Maurcio HETP/HTU=eficiciency

Jawwad Khan HETP is generally used for distillation.. And HTU for gas absorption or stripping....

Er Dhaval Patel

Hetp=shows height of theorytical stages &htu=shows that height of colum

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Ivan Montiel

could you give me some information for the glycerin process

Name comment

Abdallah EL-Gharbawy

glycerin can be produced via two routes : the first one from oil and fats by reaction of oil with alchol (methanol & ethanol ) and then we get biodiesel and glycerol


the second routes from chlorination of propylene to give allyl chloride, which is oxidized with hypochlorite to dichlorohydrins, which reacts with a strong base to give epichlorohydrin. Epichlorohydrin is then hydrolyzed to give glycerol. Chlorine-free processes from propylene include the synthesis of glycerol from acrolein and propylene oxide.

Er Dhaval Patel

Glycerine is bye product of soap mfg and produce of fat or oile

Prejilesh Vanimel

Triglycerides of fatty acid(oil) can split into fatty acid &glycerin with high temprature&pressure

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Mohit Tiwari

Difference between total dead heat & dead head at max. impeller centrifugal pump

Name comment

Ah.yehia

You can deadhead a centrifugal pump if you operate it full of liquid with the inlet and outlet valves closed, so there is no flow through the pump. In this case, the rotating component of the pump (impeller) will continue to agitate the same volume of liquid. Danger The danger of deadheading a centrifugal pump is that, as the liquid rotates, frictional forces cause its temperature to rise to the point where it vaporises. The vapour disrupts cooling of the pump and may cause excessive wear and tear to its bearings. Deadheaded centrifugal pumps have been known to explode even if they contain just water or brine.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Mohit Tiwari

Difference between total dead heat & dead head at max. impeller centrifugal pump

Name comment

Ah.yehia

Protection A centrifugal pump can be protected from the effects of deadheading by fitting a line, upstream of the outlet valve, to recycle liquid back to the inlet valve. The diameter of the line should be sufficient to recycle enough liquid to prevent the pump overheating.

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Faizan Arshad

Is stichoimetry compulsory for chemical engineering ?

Name comment

Narendra Naren Kumar

s it's important

Duraisamy Gopalakrishnan

s ofcourse.

Devendra Gurjar

Yes

Muneeb Ur Rahman

Yes as it helps to achive desired product details. As well as it izs the basis for mass and heat transfer calculations which are used to design equipments.

Junaid Ahmed yes

Er Dhaval Patel Yes it is important

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Edmon A. Qusar

dose the activation energy change with particle size when finding the rate equation? or in another way dose the activation energy affect with the particle size when finding the rate equation?

Name comment

Mohit Tiwari I think it is only function of temperature hence will not change with particle size

Jama Salimov

students opinion: activation energy can be calculated using Arrhenius equation, which is k=-A*e^(-Ea/RT) I don't see a direct correlation, but increased particle size will give smaller mass transfer area, hence heat transfer area will be lowered, which indirectly impacts rate of equation. I doubt there is a strong impact.

Mohit Tiwari

I think particle size matters in collision theory as it reduces the no. of affecting collision of all particles hence reduction in temp & rate reaction but no effect in consideration for arrhenius equation

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Edmon A. Qusar

dose the activation energy change with particle size when finding the rate equation? or in another way dose the activation energy affect with the particle size when finding the rate equation?

Name comment

Mohit Tiwari Large particle size as per collision theory will reduce the kinetic energy & hence activation energy

Malus Prathmesh

nope activation energy will not chnge...mohit correctly pointed out.....it is a function of temperature


activation energy only depend on temperature

Muneeb Ur Rahman

In collision theory, formation of products takes place when reactant molecules collide with a certain minimum energy to form product molecules. Hence at same temperature more energy is required by bigger molecule to move and collide compared to smaller one. Therefore activation energy is more for bigger molecule at constant temperatue.

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Gokul singh

What chemical reaction not exothermic or endothermic or third way is possible or not ?

Name comment

Ah.yehia

* An endothermic reaction is any chemical reaction that absorbs heat from its environment. Here's a list of examples of endothermic reactions. You can use these when asked to cite an example or to get ideas to set up a demonstration of an endothermic reaction or process. * Endothermic Chemical Reactions reaction of barium hydroxide octahydrate crystals with dry ammonium chloride dissolving ammonium chloride in water reaction of thionyl chloride (SOCl2) with cobalt(II) sulfate heptahydrate mixing water and ammonium nitrate mixing water with potassium chloride reacting ethanoic acid with sodium carbonate photosynthesis (chlorophyll is used to react

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Gokul singh

What chemical reaction not exothermic or endothermic or third way is possible or not ?

Name comment

Ah.yehia

Endothermic Chemical Reactions carbon dioxide plus water plus energy to make glucose and oxygen) Endothermic Processes * These examples could be written as chemical reactions, but are more generally considered to be endothermic or heat-absorbing processes: melting ice cubes melting solid salts evaporating liquid water converting frost to water vapor (melting, boiling, and evaporation in general are endothermic processes) making an anhydrous salt from a hydrate forming a cation from an atom in the gas phase splitting a gas molecule separating ion pairs cooking an egg baking bread

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


I want references about bio gas plz

Name comment

Micha Kisielewski

http://www.amazon.com/Biogas-Waste-Renewable-Resources-Introduction/dp/3527327983

Selvavinayagam Santhanam

how to prepare organic fertilizer at home from domestic waste?

Name comment


by anaerobic digestion

Gokul Singh

Like a composte, we take a large chamber and biodegradable waste collect in this chamber, add water in this chamber, and aerobic and anaerobic degration take place, the reaction enffluent or product use as a organic fertiliser.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Sahil Satwara

if non condensable is added inthe distillation column , so what's the effect in the dew point of the distillate . .whether it will increase or decrease? And why

Name comment

Peto Wagih

Look, I'm not sure of my answer but dew point is the point at which the first drop of liquid appears, So assuming that there is no chemical reaction between the non condensing material added and the existing material and also assuming the same pressureand temperature applied, I don't see a reason why should dew point change in the first place....I mean, it is function of pressure and temperature in the first place so by not changing these factors all what changes is the "amount" of liquid not "dew point".

Ahmed Yehia i think it has no effect

Md Han

INCREASES DUE TO INCREASE IN PRESSURE !!

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Sahil Satwara


Name comment

Mohit Tiwari

When vapor condenses in condenser of column @dew point provide a wet surface but then non condensable surrounds this surface & then vapor will first diffuse through this film of non condensable (additional gas phase resistance) which provide resistance to vapor reaching towards dew point hence dew point increases & load of condenser increase & therefore reflux ratio decreases & hence will be requirement of more no. of trays in enriching section of column.

Mohit Tiwari

as i think non condesable provide resistance to vapor i.e work like inert & there will be problem in phase transfer from bubble pt. to dew point

Osama Abdallha

decreases because of high pressure which will be developed

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Sahil Satwara


Name comment

Abo Gooda I think it will decrease

Clint Regondola

Mohammed

increases due to Dalton's and Raoult's law

Z Maurcio pi dec. (Dalton); xi dec. (Raoult); then yi inc. and dew point increase.

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Nidhi Satwara

What is the cheapest form of polymer?

Name comment

Zeeshan Amjad Malhi polythene

Abdelrahman Mohamed Khalid

linear polymer

Alexander John Rico polyethylene

Jeevarathnam Joseph Polythene

Raghu Can Can polythene

Tulio Yterbio Fernandes Vale

It's polyethen

Harish Ch polystyrene

Gokul Gokz polyethen

SaintYago Pincay polyethylene is the most economic globally

Gopal Danu 1polyethylin

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Nidhi Satwara

What is the difference between a simple and long chain polymer?

Name comment

Manne Nirmal Kumar

A simple polymer consists of a long chain of monomers joined by covalent bonds

Zeeshan Amjad Malhi

Polymers are repeating units of atoms that form a chain, as the length of this chain increases, the polymers molecular weight increases. Simple polymers are by definition then, short chain, low atoms per molecule, structures. Longer chains equal larger molecular weight polymers. Longer chains incorporate polymers with a lot more diversity in applications, like high density plastics with high melting temperatures, abrasion resistance (rubber , urethanes and such)

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Nidhi Satwara

What is the difference between a simple and long chain polymer?

Name comment

Mohamed Serag Eldeen

if u ask about measuring? it must have higher viscosity

Er Dhaval Patel Simple polymer contain only 1monomar but chain polymer contain monemar in series.

continue

Yucef Tawes

can any one help me to find information about Harriot method for calculation of diffusion coefficient

Name comment

Abhilash Narnaware

www.sciencedirect.com u can search here

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


AhMed HAssan

what is the MAX temperature allowable for a heat exchanger AS CWS COOLING WATER SUPPLY ?

Name comment

Krunal Shah It's depends on the condition...in hot conditions It is around 55C to 60C

Z Maurcio It depends on plant and local

Sana Ullah it's not fixed

Mustafa M Hathal Alfukaiki

dew point

Yuosuf Al Faraj we usually supply cooling water at 35C, so i think the max temperature will be 40 to 45.

Raghu Can Can i think up 2 its bubble point


bubbling point

Robin Pv i thnk it is 30

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


AhMed HAssan

what is the MAX temperature allowable for a heat exchanger AS CWS COOLING WATER SUPPLY ?

Name comment

AhMed HAssan

answer 50c as more than this calcium carbonate and potassium carbonate may accumulated again and make fouling probs.tand corrosion prob. ref:Guide to process equipment book

can you give me references for production of dimethyl ether

Name comment

Sana Ullah Turton,R.et al : Analysis, Synthesis and design of Chemical Processes, 1998. Page Number 709 to 711

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Nidhi Satwara

What role does the Ventury effect have on mixing chemicals?

Name comment

Azhar Mushtaq it decrease the effect of pressure and increase the mixing of chemical

Z Maurcio speeding velocity

Muneeb Ur Rahman

Reduces mixing time

Nidhi Satwara

How can i check the purity of Kcl?

Name comment

Tulio Yterbio Fernandes Vale

Volumetric analisys acid/base

Amr Waly titration vs NaOH

Z Maurcio Constant current coulometry and ion chromatography to subtract bromide

Er Dhaval Patel Colaromatry titration

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Nidhi Satwara

Which chemical will you add to water to increase the viscocity to 40 centipose?

Name comment

Utpal Pohane polyacrylamide & XANTHANUM GUM

Er Mayur Patil i think..........polyacrylamide or xanthanum gum is right ans...

Santosh Kumar Bhavirisetti

PEG

Hasan Salamah carpobol

Yuosuf Al Faraj agar, but the question is what is the fraction of agar should be added to raise water viscosity to 40 cintypose?

Gagan Deep Kalra Agar agar is rite answer

Dheeraj Kumar Yarlagadda

polyacrylamide

Er Kapil Maan Agar agar sol is the mixture of various carbohydrates

Josue Mateus Bohn

Agar Agar

Himanshu Sharma I thnk it is agar agar solution

Abhishek Verma honey

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Zafir Imam

Esterification reaction is endothermic or exothermic?

Name comment

Alaa Khaled Meetkees

exothermic

Gokul Singh

Endhothermic reaction, and reversible, water formation take place, it is major to remove it, otherway potential got backward direction

Koushik Aguan endo

Sanjay Khatri Exothermic rxn

Moni Velasco levemente endotermica

Ronak Raiyani

It is mainly exothermic reactions but when the esterification generates a cyclic ester they tend to be endothermic reaction...!

Shraddha Deshmukh

endothermic

Jeevarathnam Joseph

Endothermic reaction.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Zafir Imam

Esterification reaction is endothermic or exothermic?

Name comment

Nimit Vasani Endothermic....beacuse u need heat to evaporate water from alcoholic group

Hiren Gohil endothermic.

Er Dhaval Patel Endothermic reaction

Roshan Tembhurne

Endothermic dude

Kiran Bhatreja Exothermic reactn

Faisal Panhwar Endo.

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Trisha Sharma

can u suggest me whether chemical engg. Hv scope in India...?

Name comment

Usman Naseem Yes Gutka is a Chemical, you can have your own gutka stall at Railway station..

Prathap Selvam no scope..

Anil Kumar Really no scope at all

Brijesh Rana nt for girls......... really

Sachin Chavare

scope is what? how you take challenge is scope...n India has very big scope for Chemical Engineers...All the best.

Nirali Rana Yes...lots of scope...depends on u n ur knowlage.

Roshan Tembhurne

Lots of

Vishnu Soman Kannankara

Of course yes....! but it only depends upon u.

Mohit Sharma Yes

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Abhishek Verma

What is the difference between extensive and intensive properties ?

Name comment

Engr Muhammad Ali

intensive properties are independent of mass while extensive depends upon mass

Arthur J Shih

If you cut a system in half, quantities that change are extensive, and quantities that don't change are intensive.

Ronak Raiyani

An intensive property is one whose value does not depends on the amount of the substance for which it is measured.i.e: Temp.,Sp.Gravity,Atm.Pressure etc. while, Extensive is one that value depends on quantity of matter in the system.i.e.;Entropy,Enthalpy,Volume,Gibbs Energy etc.

Er Dhaval Patel Intensive properti independent of mass&extensive property bepend on mass

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Abhishek Verma

What is the difference between extensive and intensive properties ?

Name comment

Taha Siddiqui extensive property do not depends upon mass while expensive does

Er Kapil Maan

Intensive property are bulk property means physical properties of system bt the extensive are interacting the subsystem

Hasan Salamah in. depends on mass while exdoeant depend on mass

Vishnu Soman Kannankara

Intensive-independnt of mass

Omar Samir Hence all specific properties are intensive

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Raghu Can Can

can u explaine about split type heat exchanger Name comment

Rajashekar Chilukamari

the manufacturer of all types of Split Type Steam Heat Exchanger For Rice Parboiling Plant. it is engaged in the production and distribution of premium quality Split Type Steam Heat Exchanger For Rice Parboiling Plant in the industry. These Heat Exchangers we supply in the market is known for it high precision performance. In case tube leakages in heat exchanger, every tube Is repairable in your mill Cleaning system is very comfortable, open to the framing both and cleaning the every tube Steam goes to the multiple header instead of standard type one header that increase efficiency of heat exchanger & then reduces the drying time and save the husk In case lot of tubes leakages in Heat exchanger, remove only leakage part and join the new part. No need to change total heat exchange

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Kavi Arasu

How much water occupy in a 1" inch s.s pipe of length 10 meter ??? How can we calculate?

Name comment

Muhammad Usman

Think of the pipe as a cylinder, volume of cylinder is pi*r^2*h where h will be 10 m, radius would be the innder radius of the 1 inch pipe by the way. Volume would be how much water can that pipe occupy

Mohammed Salih

volume=3.14*r^2 *h

Koushik Agarwal

5064.5 cc

Hemant Rautela

5.064506 liters of water

Pandurang Chate

Pi/4 X d X d X L... d is inner diameter

Z Maurcio 5 L, uff.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Raghu Can Can

What is wet vacuum and dry vacuum and compare both

Name comment

Nitin B Sasane

vaccum containing moisture is wet vaccum. and no misture available is dry vaccum.

Ahmed Yehia

* i think dry vacuum that happened where complete separation between vapors and liquids so vacuum will occur in gas phase 100% * on the other hand, wet vacuum happened in gas fraction phase mean media is vapors and some liquids * i don't sure that

Anbarasan Sankaran

Liquid particle present that is wet vacum. There no liquid particle it is dry vacum.

Raghu Can Can

Wet vacuum means in ejector if we use steam and create vacuum means that is wet vacuum neither we use air means that is dry vacuum but I don't know why they r using wet r dry vacuum

Murthy Meduri Balaji

Use of steam differentiate both

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Dinakar Satya

why hydrogen is exception for joule thomson effect?

Name comment

Ahmed Mohamed

Khalil

At room temperature, all gases except hydrogen, helium and neon cool upon expansion by the JouleThomson process. the exception for hydrogen, helium and neon is due to (the very low inversion temperatures) of them which is -68C for H2,222 C for helium at Atm pressure. this make them warm up when expanded at constant enthalpy at typical room temperatures.

Djohan Khairudin

When release to atmospheric pressure,it heats up.

Z Maurcio

Molecular interaction too weak. Helium, Neon and hydrogen are tree gases whose JouleThomson inversion temperatures at a pressure of one atmosphere are very low (e.g., about 51 K (222 C) for helium). Thus, they warm up when expanded at constant enthalpy at typical room temperatures.

Raghu Can Can

these hydrogen and helium r more reactive groups

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Dinakar Satya

why hydrogen is exception for joule thomson effect?

Name comment

Anup Ca bcz of -ve joule thomsn coefficient....that means :increase itz(H2)temp in throatling process.

Ronak Raiyani

& More cheaper than argon, krypton, xenon, niyon etc Becoz it is noble gas.

Nirav Gandhi

Hydrogen is not follow joul thomson effect iir reversible

Anup Ca Helium is an another example.

Fabio Augusto

Hydrogen is an exception in a certain range of P and T, but it is not the only exception.

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Dinakar Satya

i want to know where the distillation coulumn will be used in a horizontal position? and how will be the operating conditiones?

Name comment

Arthur Shih

It's possible, but it's not feasible. The reason why distillation columns are vertical is so that (1) gravity can pull the liquid phase downward and (2) trays/packing will allow adequate contact of the liquid and vapor phases. Horizontal distillation columns will not only require two extra pumps (one for the vapor and one for the liquid, because gravity cannot provide the energy anymore), but it will also need some sort of mechanism to maximize contact between the vapor and liquid phases. When the distillation column is vertical, gravity and trays/packing achieves both of these.

Suraj Chaudhari

What....am not heard before this... Do anybody used distillation kettle in horizantal plane...? No its not possible

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Dinakar Satya

i want to know where the distillation coulumn will be used in a horizontal position? and how will be the operating conditiones?

Name comment

Arthur Shih

I also want to point out that vertical towers also save valuable land space. One disadvantage of vertical towers is that it requires more piping (you need to pump the tops product all the way down the length of the pipe to the condensers), but the advantages greatly outweigh the disadvantages which is why they've become the "standard" in the past 100 years.

Suraj Chaudhari

What....am not heard before this... Do anybody used distillation kettle in horizantal plane...? No its not possible

Er Dhaval Patel

Itis practical not feasiable

Z Maurcio At space, rotating!

Mohammed Salih

as used in oil refineries

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Atul Gourh

Can we use CSTR for gaseous reactant ??

Name comment

Nirali Rana

Generaly CSTR is used for uniform mixing n in gasious reactant its hard to mk perfact mixing..before mixing day react...so PFR is more preffrable...according to me.

Hasan Salamah it's better to use PFR

Nafees Ahmad yes some time, in the presence of media (liquid)...i.e HDPE process

Er Dhaval Patel Yatai Mike No

Ajit Salve Vivek Shukla no

Rita Youfa no, cstr 4 liq-liq or solih-liq

Antreas Koumouris we use them for slow liquid phase rxns mostly


NOP

Davey Uloma Ghaith Alsaidi No

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Murthy Meduri Balaji

Can we use liquid DAP instead of granules? As it will reduce the cost of granulation,drying, cooling

Name comment

Bujji Fireheart

ya bt bt the cost depends on farmers farmer lost so much of monney its not gud product for farmer and handling too hard calculation is too confused for former

Salahuddin Rajput

*Difficult to calculate (Dilution Required) *Poor Handling *Consume too quickly (Drawback) *it will stay on the leafs (can harm/damage the leaf) due to excess nitrogen *granule release adequate amount in particular time while liquid spills and absorbs quickly by the soil.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Saurbh Salfale

Would you please tell me what is the maximum suction head for centrifugal pump in case of negative suction??

Name comment

Suraj Chaudhari Jit Sumon 10.30 bar

Anup Ca 10.33 m water

Pravin Patil 10.33 m water (34 feet)

Syed Shah Jehan Gillani

10 m

Saurabh Salfale

But i need an explaination over this... I think it may related with the concept of vapour pressure of the pumping fluid bcoz when vapour pressure of the pumping fluid is equal to atm. press then cavitation will takes place due to boiling.

Yatish Banakar

For 1kg/cm2 it will give 10.33mts head, section wil play important role during starting of pump.. If negetive need to give priming. When vp is equal atm then boiling takes place

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Bright Izuchukwu

xplain d principles of the heat xchanger wen fluid flows counter currently

Name comment

Sanjay Khatri A device is used for exchanging or transfering energy heat between the fluids.

Chirg Mahyavanshi

if fluid in counter current den heat trnsfer take place will be more bcoz of counter current fluid directin n residence time between two fluid will b mor.so it creat high ht n low require energy.

Er Rajvi Garg heat transfer co-efficient will be more if the flow is counter current

Vibha Mishra heat transfer will be more , contact tym is more heat loss wiil be less and heat transfer coefficient will be more.

Pandurang Chate

Heat is getting transferred from hot fluid to cold fluid. Being counter current flow, area of heat exchanger is much lower than cocurrent flows becuase of higher LMTD(Log Mean Temperature Difference)

Z Maurcio The coolant can get hotter than the fluid cooled.

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Bright Izuchukwu

xplain d principles of the heat xchanger wen fluid flows counter currently

Name comment

Mohammed Salih

heat is transferred in three different ways, conduction,convection,and radiation

Suraj Chaudhari

There is more contact surface area nd contact time for exchange the heat and low exotherm nd optimum operational cost

Sha Geck

@mohammed salih: heat exchangers exchange heat between the process fluid and cooling fluid by means of conduction and convection.. Not by radiation..!

continue

Sen

d y

ou

r q

ues

tio

n a

nd

we

will

po

st it

on

ou

r p

age

wal

l


Dinakar Stya

how nuclear fusion and fission will takes place at a time in hydrogen bomb?

Name comment

Mohamed Ahmed Fouad

The energy required for nuclear fusion comes from uranium splits which results in fussion and release a large amount of energy. So, in hydrogen bomb nuclear fission of uranium first takes place then nuclear fusion of Deuterium and tritium takes place.

Nidhi Satwara

uses of vinyl sulphone ester ?

Name comment

Er Dhaval Patel

It is used as intermideate in dyes stuf industry.


Designed by Ah.Yehia

2013

IamCheEng Magazine 6-2013

Documents

Transcript of IamCheEng Magazine 6-2013